For better or worse, international aviation and shipping aren’t covered by national emissions plans. They’re treated through separate agreements, such as the one on aviation negotiated this year. That doesn’t mean we can ignore it, but it does mean that the government won’t feel much obligation to act on aviation or shipping.

The bit it can focus on is domestic emissions, and it’s very obvious what the biggest problem is. So what do we mean by surface transport? Here’s how that divides up:

By some distance, the biggest source of transport emissions is cars – and…